En la presente investigación se buscó establecer una relación entre la regulación emocional y la expresividad emocional, así como realizar correlaciones y comparaciones entre las variables de estudio y demográficas. Para ello, se evaluaron a 163 docentes del género femenino, tanto profesoras como auxiliares, con una media de 33 años de edad, que ejercían en diez diferentes jardines de educación inicial privados de Lima. Se utilizó el Cuestionario de Autorregulación Emocional (ERQ-P), el cual mide dos estrategias, la reevaluación cognitiva y la supresión emocional. Además, se aplicó el Cuestionario de Expresividad de Berkeley (BEQ) para medir la expresividad emocional, que abarca la expresión de emociones positivas, negativas y la fuerza del impulso. Se comprobó que sí existe una relación significativa entre la reevaluación cognitiva y la expresividad positiva, demostrando así la hipótesis principal. Además, se encontró una correlación negativa entre dicha estrategia y la edad de los niños a cargo, así como también se hallaron diferencias significativas al realizar comparaciones entre la muestra, obteniendo que el grupo de las docentes que son madres, y las del cargo de profesoras, expresan más emociones positivas. Es de gran valor el rol de las docentes para el aprendizaje de la regulación y la expresión emocional en los niños, resultando necesario que las mismas logren regularse adecuadamente, ya que cumplen de modelos en dicho aprendizaje observacional. Finalmente, se señalan las limitaciones del estudio, como lo fue descartar la supresión por baja confiabilidad, y las implicancias prácticas en la labor y formación docente. / The present investigation intended to establish a relation between emotion regulation and emotional expressivity in private Pre-School teachers and helpers of Lima, as well as correlate and compare the study and demographic variables. Therefore, 163 female teachers and helpers from ten different Pre-Schools were measured, and the mean age was 33 years old. There are two main regulation strategies, cognitive reappraisal and emotional suppression. On the other hand, emotional expressivity covers positive expressivity, negative expressivity, and impulse strength. These variables were measured with the Emotion Regulation Questionnaire and the Berkeley Expressivity Questionnaire. Results showed that cognitive reappraisal correlated positively with positive expressivity, demonstrating the main hypothesis. Also, this strategy correlated negatively with children’s age, and as of the comparisons, there were significant differences between teachers and helpers, and between mothers and non-mothers, regarding positive expressivity. Since teachers and helpers play the valuable part of being models in children’s learning process of regulation skills, it is crucial they manage to regulate their own emotions adequately, given its impact on their socioemotional development. At last, limitations and future implications are mentioned, so as the removal of emotional suppression due to low reliability, and the practical implications of this study regards the work, training and education of teachers and helpers. / Tesis

The conceptual model of emotion regulation (ER) of Gross and Thompson (2007) introduces families of ER strategies ordered on a temporal scale. This scale has been attributed implications both for the grouping strategies but also for the neurocognitive processing. The two event-related potential (ERP) studies of emotional regulation presented here focus on emotional regulation at different temporal distances, as well as, different stages of cognitive processing. Trying to discern if various neural processes could be disentangled by looking at different stages of the late positive potential (LPP). The theoretical background begins with the neurocognitive science of emotionality and visits cognitive processing at both early and late stages before summating results of the contemporary research of emotional regulation. 39 participants were enrolled within the two experiments aiming to compare the efficiency of different strategies in reducing negative social emotion induced by photographs of angry faces. Technical difficulties discourage conclusions about how temporal distancing is most effectively adapted. Results suggest self-focused distancing strategies are more effective than situation-focused reappraisal and could be preferred for therapeutic purposes based on greater observed LPP effect.

Contexte : La régulation émotionnelle est un ensemble de processus responsables du contrôle, de l’évaluation et de l’ajustement des émotions dans un objectif. Les résultats d’imagerie fonctionnelle s’accordent sur l’implication des structures frontales et limbiques tandis que les résultats en neurophysiologie, encore rares, suggèrent un rôle du rythme alpha dans l’induction émotionnelle et du rythme thêta dans la régulation. Objectifs et hypothèses : Notre objectif était d’étudier le rythme thêta et alpha pendant la réévaluation de stimuli déplaisants. Nous avons émis l’hypothèse que l’activité alpha serait modulée lors de l’induction émotionnelle seulement tandis que l’activité thêta préfrontale serait positivement corrélée à une régulation réussie. Méthode : Vingt-quatre participants sains ont été enregistrés avec 64 électrodes EEG alors qu’ils regardaient passivement ou réévaluaient des images négatives et neutres. Les rythmes thêta et alpha ont été comparés lors de l’induction émotionnelle puis dans les conditions de maintien, de diminution et d’augmentation de l’émotion, et une localisation de la source a estimé les générateurs. Résultats : Le rythme alpha était non sensible à l’induction et à la régulation. L’activité thêta était systématiquement plus élevée dans la condition de régulation à la hausse que dans la condition de maintien (p=.04) principalement au début de la régulation (1-3 sec) pour thêta bas et plus tard (5-7 sec) pour le thêta haut avec comme générateur du thêta bas le gyrus frontal moyen et le cortex cingulaire antérieur dorsal. Conclusion : Le rythme thêta était impliqué dans les processus de réévaluation à la hausse de l’émotion. / Context: Emotion regulation is a set of processes responsible for controlling, evaluating and adjusting reactions to achieve a goal. Results derived from magnetic resonance imaging agreed on the involvement of frontal and limbic structures in this process. Findings using cognition and physiology interactions are still scarce but suggest a role for alpha rhythm in emotional induction and theta in regulation. Objectives and hypotheses: Our goal was to investigate theta and alpha rhythm during the reappraisal of aversive stimuli. We hypothesized that an implication of alpha rhythm in emotional induction only and an increase in prefrontal theta rhythm positively correlated with successful regulation. Method: Twenty-four healthy participants were recorded with 64 EEG electrodes while asked to passively watch or reappraise negative pictures. Theta and alpha rhythms were compared across maintain, decrease and increase regulation conditions, and a source localization estimated the generators. Results: Theta activity was consistently higher in the upregulation than in the maintenance condition (p=.04) for the entire control period, but mainly at the beginning of regulation (1-3 sec) for low-theta and later (5-7 sec) for high-theta. Moreover, our results confirm that a low-theta generator correlated with mainly the middle frontal gyrus and the dorsal anterior cingulate cortex during upregulation. Theta was sensitive to emotion upregulation, whereas the alpha oscillation was non-sensitive to emotion induction and regulation. Conclusion: The low-theta rhythm was involved explicitly in emotion upregulation processes that occur at a definite time during reappraisal, whereas the alpha rhythm was not altered by emotion induction and regulation.

Parenting stress has been closely studied largely in relation to implications for the parent and implications for children. Emotion regulation refers to the processes in which one interprets and experiences emotions. Little has been done examining how parenting stress and mother emotion regulation relates to dyadic interaction between mother and child. Because of the compounding nature of stress as identified in the ABCX model of family stress and resilience theory, understanding parenting stress in its entirety and how mothers experience and deal with said parenting stress is crucial to understanding family processes, as it is not possible to partition the mother and child into separate spheres, per family systems theory. Maternal parenting behaviors cannot be conceptualized in isolation of the mother-child dyad; therefore, it is important to understand maternal processes and behaviors that relate to parenting and also the dyad. The current study examined the moderating impact of maternal emotion regulation on the relation between maternal parenting stress and three facets of dyadic interaction, including conflict, cooperation, and reciprocity. Mothers and their 4-5.5-year-old children (n=116) participated in a teaching task wherein mothers instructed their child to build figures with interlocking blocks based on provided images. Six hypotheses were examined. Regression analyses revealed that neither maternal cognitive reappraisal nor maternal emotion suppression moderated the relation of total parenting stress to parent-child dyadic interaction. However, preliminary correlation analyses revealed that dyads with boys experienced higher scores of dyadic conflict. Boys in the sample were also younger than girls. Considerations for lack of significant findings are explored including the role of maternal characteristics, child characteristics, and goodness-of-fit. Future exploration is necessary to examine how parent characteristics like maternal emotion regulation and parenting stress may relate to dyadic interactions with children. / M.S. / Most of the research on parenting stress, which is the stress that parents may feel related to their roles as parents, examines how it is related to parenting behavior or directly to their children’s behavior. There is little research on how parenting stress and maternal emotion regulation, which how mothers control their emotions, relate to dyadic interactions between mothers and children. Theories of family stress suggest that stress builds over time; therefore, it is important to understand all aspects of parenting stress. When any family member experiences stress, theories suggest that their stress can affect other family members. Maternal parenting behaviors, however, cannot be viewed separately from patterns of dyadic interaction between mothers and children; it is important to understand how maternal characteristics, including parenting stress and emotion regulation, relate to patterns of dyadic mother-child interaction. The current study examined how maternal parenting stress related to three types of dyadic interaction, including conflict, cooperation, and reciprocity. It was expected that how parenting stress would relate to dyadic interaction would be different depending on how mothers reported regulating their emotions. Mothers and their 4-5.5-year-old children (n=116) participated in a building task where mothers taught children how to make figures out of interlocking blocks based on pictures provided to mothers. Findings showed that maternal emotion regulation did not increase or decrease how maternal parenting stress related to dyadic interaction between mothers and children. Dyads with boys, however, experienced higher scores of dyadic conflict, and boys in the sample were also younger than girls. Future exploration is needed to examine how parent characteristics like maternal emotion regulation and parenting stress may relate to dyadic interactions between mothers and children.

過去研究顯示負向情緒會干擾夜間睡眠，預期可有效降低負向情緒的情緒調節策略應有助於睡眠，然而，認知再評估策略對睡眠的影響卻未有一致的研究結果，此可能受限於過去研究多以問卷測量認知再評估策略的使用偏好，卻未測量個體使用策略的能力，亦即認知再評估策略的調節效果。本研究透過實驗室典範測量認知再評估能力，主要探討個體使用認知再評估策略的能力是否會影響個體於夜間情緒調節的效果，以及再評估策略於睡前之適用性。本研究受試者共24位，包含11名男性與13名女性，平均年齡為22歲。受試者皆依序經歷引發和調節負向情緒的實驗情境與中性情境兩個夜晚，並以主觀問卷與客觀生理反應測量受試者使用認知再評估策略調節情緒的表現，及對其後續睡眠的影響，在兩晚作業結束後，受試者會回到實驗室進行認知再評估能力測量作業。研究結果發現，認知再評估能力佳者於實驗晚的情緒調節表現較佳，在能力指標中，正負向與憤怒感調節佳者，其睡前生理激發度增加量較低、入睡前高頻腦波相對功率較低，且較不會高估入睡耗時；此外，運用再評估策略會增加較高情緒控制感者，入睡後高頻腦波相對功率較低，且實驗晚所增加的入睡耗時較低。整體來說，負向情緒會干擾後續睡眠，於正負向指標上調節能力佳者較可減少其主觀失眠困擾度，且使用再評估策略後有較高情緒控制感者，較可彈性的運用再評估策略。 / Negative emotion has been showed to interfere with sleep, therefore effective emotion regulation to reduce negative emotion prior to sleep could be beneficial for sleep. Cognitive reappraisal is generally considered to be an effective and adaptive emotion-regulation strategy, but previous studies had inconsistent findings about the impact of reappraisal on sleep. A study has even found that insomnia patients had a higher frequency to use reappraisal in comparison to good sleepers. However, previous studies used self-report measure of an individual's tendency to use reappraisal. It has been shown that the frequency of using reappraisal did not correlate with the ability to use reappraisal as measured by reduction of stress reactivity after standard laboratory challenge. The present study examined the hypothesis that the impact of pre-sleep reappraisal on sleep onset process depends on individual's cognitive reappraisal ability (CRA). Twenty-four normal sleepers were recruited (male:11, female:13, average age: 22 years). Participants came to sleep laboratory for two experimental nights and one daytime reappraisal ability evaluation. For the two experimental nights, participants did a cognitive task and got two different feedbacks for the two conditions: either a neutral feedback (baseline condition night) or a negative feedback (experimental condition night). They were instructed to use cognitive reappraisal strategy to reduce negative emotion after getting negative feedback. The change of subjective emotion ratings and physiological reaction were measured during the presleep task. Polysomnographic recording and subjective ratings of sleep onset experience was conducted for the sleep onset process analysis. During the daytime session, the ability of the participants to use reappraisal was measured with physiological reactivity to a standard laboratory challenge with anger-inducing films. The results showed that, at experimental night, participants with high CRA in reducing emotion valence exhibited better emotion regulation outcomes, less presleep somatic arousal increments, lower beta power before falling asleep, and less overestimation of their sleep onset latency (SOL). Besides, participants with high CRA in reducing dominance of emotion exhibited shorter emotion regulation time, lower beta power after falling asleep, and lesser SOL increments. This finding is consistent with the hypothesis that reappraisal ability would determined whether cognitive reappraisal strategy is adaptive for presleep emotion regulation; those individuals with better CRA in reducing dominance of emotion might have more flexibility in applying reappraisal strategy.

La forte prévalence des conduites alimentaires à risque (CAAR), par exemple la restriction alimentaire, les vomissements auto-induits ainsi que les crises d’hyperphagie boulimique de sévérité non diagnostique, et les conséquences importantes qu’elles peuvent entraîner ont amené les chercheurs à vouloir mieux comprendre les facteurs impliqués dans leur développement. Cette thèse s’intéresse à un phénomène à la base d’un nombre grandissant de théories sur les CAAR : la régulation émotionnelle. Le premier article se concentre sur le concept d’alexithymie, un trait de personnalité jouant un rôle clé dans la régulation émotionnelle ainsi que le développement, le maintien et la rechute des CAAR. Bien que l’association entre l’alexithymie et les CAAR soit bien établie, les études n’offrent pas d’explication quant aux facteurs qui contribuent à l’apparition de traits de personnalité alexithymiques qui, à leur tour, placent l’individu à risque de développer des CAAR. En explorant la documentation scientifique disponible, il est possible de constater que plusieurs psychanalystes ont autrefois proposé des concepts pour expliquer le développement de l’alexithymie (p. ex. refoulement primaire, expérience non formulée, déni), mais ces théories ont rarement fait l’objet d’études empiriques. L’objectif du premier article est donc de tester ces modèles en utilisant deux stratégies de régulation émotionnelle provenant du modèle de James J. Gross, soit la suppression expressive et la réévaluation cognitive. Un échantillon de 292 femmes provenant majoritairement d’une population non clinique universitaire a complété le Toronto Alexithymia Scale-20 items, le Emotion Regulation Questionnaire et le Eating Disorder Inventory-2. Les résultats des médiations proposent que la suppression expressive prédit positivement les traits de personnalité alexithymiques, ce qui prédit positivement les CAAR. Inversement, la réévaluation cognitive prédit négativement les traits de personnalité alexithymiques, ce qui prédit ensuite négativement les CAAR. Ces résultats suggèrent qu’il pourrait être pertinent d’intervenir sur certains mécanismes potentiellement précurseurs de l’alexithymie afin de favoriser la diminution d’agirs comportementaux comme les CAAR. Les résultats de cette première étude ouvrent la réflexion sur des pistes d’intervention concrètes pouvant être mises en application auprès des personnes souffrant de CAAR. En effet, les résultats de cette thèse suggèrent qu’il pourrait être important d’aider l’individu à diminuer l’évitement/la suppression de ses émotions pour plutôt encourager leur exploration. Il est possible d’émettre l’hypothèse que ce type d’intervention permettrait, avec le temps, la diminution des traits alexithymiques, ceci en favorisant la formation de représentations mentales des émotions. Conséquemment, la diminution de décharges somatiques comme les CAAR pourrait s’en suivre. L’implication des résultats pour les thérapies de différentes approches (p.ex. psychodynamique, cognitivo-comportementale et basée sur la mentalisation) est ensuite discutée. Afin de préciser l’étude de la régulation émotionnelle dans les CAAR, le second article a pour but d’identifier les émotions jouant un rôle particulier au sein de ces comportements. Pour ce faire, cet article, qui comprend deux études, s’intéresse aux liens entre les catégories émotionnelles distinctes du modèle des émotions différentielles d’Izard (p. ex. tristesse, joie) et les CAAR. La première étude a pour objectif d’explorer l’association entre les émotions-traits et les conduites alimentaires de recherche de minceur et boulimiques. Un total de 244 femmes provenant en majorité d’une population non clinique universitaire a complété le Eating Disorder Inventory-2 et le Differential Emotion Scale-trait version. Les analyses de régression démontrent que le modèle d’Izard prédit significativement les conduites de recherche de minceur et boulimiques. La contribution unique de chaque émotion-trait est ensuite étudiée. Les résultats indiquent que la honte est la seule émotion qui reste un prédicteur significatif des conduites de recherche de minceur et que seuls la culpabilité, le mépris et l’hostilité dirigée contre soi demeurent des prédicteurs significatifs des comportements boulimiques. Pour sa part, la seconde étude a pour but d’explorer l’association entre les émotions-états et les CAAR. Un total de 155 participantes provenant de l’échantillon de la première étude a complété un questionnaire leur demandant de rapporter par écrit un comportement de restriction ou de boulimie ayant eu lieu dans le passé. Elles ont ensuite complété le Differential Emotion Scale-state version. Les analyses descriptives démontrent que nonobstant la nature du comportement, la tristesse est l’émotion vécue la plus intensément par les participantes avant l’épisode rapporté. De plus, une comparaison de groupes a révélé que les personnes ayant décrit un épisode de boulimie ressentent significativement moins de joie et d’intérêt avant l’épisode que celles ayant rapporté un comportement restrictif. En résumé, les résultats suggèrent tout d’abord que les émotions négatives semblent jouer un rôle important au sein des CAAR. En ce sens, cet article appuie les recommandations de certains chercheurs à l’effet que l’intervention auprès des personnes ayant des CAAR nécessite d’inclure des volets dédiés à la régulation des émotions. Toutefois, ces études vont encore plus loin en proposant qu’il pourrait être pertinent de développer des interventions ciblées et concrètes permettant la gestion d’émotions ou de patrons d’émotions qui jouent un rôle prédominant auprès des différents CAAR. / The high prevalence of disordered eating (DE), for example food restriction, selfinduced vomiting or binge eating that are not of diagnostic severity, and the important consequences that they can entail have led researchers to further investigate the premorbid factors involved in them. The present thesis is interested in a phenomenon that is the basis of a growing body of theories on DE: emotion regulation. The first paper focuses on the concept of alexithymia, a personality trait that plays a key role in emotion regulation as well as in the development, maintenance, and relapse of DE symptoms. Although the association between alexithymia and DE is well established, current studies offer no explanation as to what factors contribute to the development of alexithymic personality traits, which in turn puts the individual at risk for DE. Several psychoanalysts have offered theoretical concepts to explain the development of alexithymia (e.g. primary repression, unformulated experience, denial), but these have not been submitted to empirical studies. The aim of the first study is to test these theories using two empirically established emotion regulation strategies taken from James J. Gross's model, namely expressive suppression and cognitive reappraisal. A sample of 292 women, the majority being undergraduated students, completed the Toronto Alexithymia Scale-20 items, the Emotion Regulation Questionnaire, and the Eating Disorder Inventory-2. The results of the mediation analyzes suggest that expressive suppression significantly and positively predicts alexithymic personality traits, which positively predicts DE. Inversely, cognitive reappraisal negatively predicts alexithymic personality traits, which then negatively predicts DE. These results suggest that it could be important to intervene on certain mechanisms that are potential precursors of alexithymia in order to promote the reduction of DE. More specifically, the results of this first study open up reflection on concrete lines of intervention that could be applied to vii people suffering from DE. Indeed, the results propose that it could be beneficial to encourage these individuals to explore their emotions rather then to avoid / suppress them. It can be hypothesised that these types of intervention will allow, over time, the reduction of alexithymic traits by promoting the formation of mental representations of emotions. Consequently, it is possible that the decrease in somatic discharges such as DE will follow. The implication of the results for different therapeutic approaches (psychodynamic, cognitive behavioral and mentalization-based) is then discussed. In order to further clarify the role of emotional regulation in DE, the second paper aims to identify emotions that play a key role in the disorder. This article, divided into two studies, focuses on the association between distinct emotional categories from Izard's differential emotions theory (e.g. sadness, joy) and pathological eating. The first study explores the relationship between trait-emotions and DE. A total of 244 women, the greater part being undergraduated students, completed the Eating Disorder Inventory-2 and the Differential Emotion Scale-trait version. Regression analyzes show that Izard's model significantly predicts both drive for thinness and bulimic behaviors. The unique contribution of each trait-emotion is then explored. The results indicate that shame is the only emotion that remains a significant predictor of drive for thinness and that only guilt, contempt and self-directed hostility remain significant predictors of bulimic behavior. As for the second study, a total of 155 participants coming from the first study sample completed a questionnaire asking them to report in writing an episode of restriction or bulimia that occurred in the recent past. They then completed the Differential Emotion Scale-state version. Descriptive analyzes reveal that regardless of the kind of DE, sadness is the emotion experienced most intensely by the participants before the reported episode. Furthermore, group comparisons indicate that people who report a bulimic episode felt viii significantly less joy and interest before the event than those who recalled a restrictive behavior. In summary, the results first suggest that people with DE experience more negative emotions on a daily basis. Thereby, this article supports the recommendations of certain researchers suggesting that interventions with people exhibiting DE should include components dedicated to the regulation of emotions. Moreover, these studies go even further by suggesting that it could be relevant to develop targets and concrete interventions allowing the regulation of specific emotions or patterns of emotions, which could play a predominant role with the various DE.

Abstract The relationship between emotion and memory has been the subject of several fascinating investigations for decades now. From a developmental perspective, research has demonstrated that episodic/autobiographical memories improve in typically developing children from an early age through adulthood. This is because of their nature in relation to processing emotional regulation strategies and recollection of traumatic or past experiences. The current systematic literature review sought to further explore the relationship between emotion regulation and episodic/autobiographical memories from a developmental perspective. The relationship was investigated using a systematic literature review in accordance with guidlines from the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. The quality of included studies was evaluated using the Study Assessment Tool for Observational Cohort and Cross-Sectional studies from the National Institute of Health. The search for empirical peer-reviewed articles yielded n=686 participants from various countries who qualified for inclusion from six databases. Due to the heterogeneity of the studies included a meta-analysis could not be done. In terms of emotion regulation strategies, emotional situation knowledge, and sensitive guidance of parental reminiscing, the results show a significant association between emotion regulation and episodic/autobiographical memories. Children as young as three years demonstrated emotional understanding and were able to recall past events, however, older children (4-older) performed better on all memory tasks, indicating that they have developed their cognition strategies well enough to outperform the younger children. Despite the positive association addressed, this systematic review observed some vaiations in the results which were noted due to the study designs included. Although few studies have advanced our understanding of the relationship between emotion regulation, episodic, and autobiographical memories, and traumatic life events, additional study is still required to better understand how these relationships develop and change over time utilizing longitudinal studies. / Sammanfattning Sambandet mellan känsla och minne har varit föremål för flera fascinerande undersökningar i decennier nu. Ur ett utvecklingsperspektiv har forskning visat att episodiska/självbiografiska minnen förbättras i typiskt utvecklande barn från tidig ålder till vuxen ålder. Detta beror på deras natur i sambandet till bearbetning av emotionella regleringsstrategier och minne av traumatiska eller tidigare upplevelser. Den aktuella systematiska litteraturöversikten försökte ytterligare att utforska sambandet mellan känsloreglering och episodiska/självbiografiska minnen ur ett utvecklingsperspektiv. Sambabdet undersöts med hjälp av en systematisk litteraturöversikt i enlighet med riktlinjerna från Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Kvaliteten på inkluderade studier utvärderades med hjälp av studiekvalitetsbedömningsverktyget för observationskohort-och tvärsnittsstudier från National Institute of Health. Sökningen efter empiriska peer-reviewed artiklar gav n=686 deltagare från olika länder som kvalificerade sig för inkludering i sex databaser. På grund av de ingående studiernas heterogenitet kunde en metaanalys inte göras. När det gäller strategier för känsloreglering, kunskap om känslöreglering situationer, känslig vägledning av förälders reminiscens, visar resultaten en signifikant samfällighet mellan känsloreglering och episodiska/självbiografiska minnen. Barn så ung som tre år visade känslomässig förståelse och kunde återkalla tidigare händelser., dock äldre barn (4 äldre) presenterade bättre på alla minnesuppgifter, vilket tyder på att de har utvecklat sina kognitivs strategier tillräckligt bra för att överträffa de yngre barnen. Trots den positiva samfällighet som adresserades, observerade denna systematiska översikt några av de flesta variationer i resultaten och noterades på grund av studiedesign som inkluderades. Även om få studier har förbättrat vår förståelse av sambandet mellan känsloreglering, självbiografiska och episodiska minnen och traumatiska livshändelser, krävs ytterligare studierna för att bättre förstå hur dessa relationer utvecklas och förändras övertiden med hjälp av longitudinella studierna.